Inferential feeding mechanism



A. H. DE VOE. DIFFERENIIAL resume MECHANISM.

PatentedSept. 23, 19.

APPLICATION FILED SEPT. 30. 1916.

2 SHEETS-SHE INVENTOR MEL/WM,

ORNEY A. H. DE VOE. DIFFERENTIAL FEEDING MECHANISM.

APPLICATION FILED SEPT. 30. l9l6- Patentd Sept. 23, 1919.

2 SHEETS-SHEET 2- 3x111?" MENTOR A TORNEY I ALBERT H. DE VOE,

OF WESTFIELD, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A COREORATION OF NEW JERSEY.

DIFFERENTIAL FEEDING MECHANISM.

Application filed September 30, 1916.

To all whom it may concern:

Be it known that I, ALBERT H. Dn Von, a citizen of the United States, residing at \Vestfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Differential Feeding Mechanisms, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to an improvement of that type of differential feeding mechanism for sewing machines, in which two feed-dogs are given equal feed-and-return movements and differential rising-and-failing movements; and it has for an object to provide mechanism of the class described 'which shall be compact, durable and effective, and which shall comprise relatively few operative parts.

In the present embodiment of the invention a primary or forwardly disposed feeddog is carried by a feed-bar or primary lever which is fulcrumed on a feed-rocker and derives its rising-and-falling movements from an eccentric on the main-shaft. The feed-rocker is fulcrumed on the machine frame and is actuated by another eccentric on the main-shaft. The secondary or rearwardly disposed feed-dog is adjustably mounted on the forward end of the second ary feed-bar or lever which extends alongside the primary feed-bar and is pivoted between its ends to the latter. The rearwardly extending end portion of the secondary feed-bar is provided with a curved slot and is anchored to a fixed point on the frame by a single link carrying a pin at its upper end which is secured in adjusted position within said slot by a thumb-nut.

In the drawings, Figure 1 is a plan View of the mechanism embodying the present improvement. Fig. 2 is a rear elevation of the same. Fig. 3 is a side elevation and Figs. 4,

5 and 6 are side views showing the relative positions of certain of the operative parts in successive stages of the feeding cycle.

In the preferred embod ment of the invention, as illustrated, the supporting frame 1 is formed with sleeved bearing lugs 22 in which are journaled the opposite ends of the fulcrum-pin 3 rigidly secured within the alined apertures in the downwardly pro- 4-4 of the feed-rocker The upper extremity is formed with 6(') for the supportect-ing spaced lugs 5. spaced bearing bosses Specification of Letters Patent.

. apertured extremity Patented Sept. 23, 1919.

Serial No. 122,954.

rigidly secured within the alined in the rearwardly projecting spaced lugs 8-8 of the main feed-bar or lever 10 which. in the present instance. is n the form of a rectangular frame. Proecting forwardly from one corner of the frame 10 is an apertured boss 11 within which is rigidly secured the pin 12 whose forwardly projecting extremity enters the usual sleeved eccentric strap 13 surrounding the feed-lift eccentric 14 on the main shaft 15 journaled in suitable bearings one of which is shown at 16. The feed-rocker is extended forwardly at one side to form an apertured boss 17 within which is secured the pin 18. The main-shaft carries an adjustable feed-advancing eccentric 19 of common form to which is fitted a sleeved eccentric strap 20 adapted to slidingly receive the forwardly projecting end-portion of the pin 18. Mounted within the guidevay -21 at the forward extremity of the main ftLKl-lffll 1O the shank of the main feed-dog 23 wluch projects upwardly and forwardly from the free end of the feed-bar 10 and 1s serrated as usual along its active upper surface 24 which at times is projected above and withdrawn below the upper surface of the throat-plate 25 by the action of the feedlift eccentric, as is well understood.

The secondary or rcarwardly disposed feeddog 26 is smaller and in the present instance is adapted to feed the work a shorter distance than the main feed-dog during each feeding cycle. To this end the secondary feed-dog 26 is formed with a downwardly extending slotted shank 2.7 adjustably secured in the forward end'of the secondary feed-bar 28 extending rearwardly ing pin 7 a perturcs alongside of the main feed-bar 10 and terminating adjacent one of the bearin lugs 6. The secondary feed-bar is formed etween its ends with a bearing boss 29 which is entered and supported by the screw-pin 30 threaded into the main feed-bar 10. The rearward end-portion of the secondary feedbar 28 is provided with a curved slot 31 within which is slidingly fitted a flattened portion and 3, journaled in the apertured upper extremity of the anchor-link 34 whose lower freely surrounds and is supported by the pivot-pin 3 of the feedrocker between the right-hand boss 4 and lug 2, Fig. 2. The fulcrum-pin has a rc- 32 of the fulcrum-screw 33, Figs. 1 I

in any desired position of adjustment along the slot 31. A washer 37 is interposed between the thumb-nut 36 and the secondary feed-bar 28, as shown in Fig. 1.

In the position of the parts shown in Figs.

1 and 3 the fulcrum-screw 33 is adjusted to the rearward .extrcmity ofthe slot 31 and the axis of the screw 33 is nearly coincidentwith the axis of the pivot-pin 7 on the main feedbar. As a result the two feed-dogs 23 and 26 are moved substantially as one throughout the feeding cycle. \Vhen the fulcrum-screw 33 is adjusted to the other extremity of the slot, as shown in Fig. 4, the rising-and-falling movements of the secondary feed-dog 26 are differentiated from the corresponding movements of the primary feed-dog 23. In Fig. l the feeddogs are at the point of emerging simultaneously above the upper surface of the throatplate 25 and the feed-rocker 5 have nearly reached its extreme forward position indicated by the dotted circle At this point in the cycle the curved slot 31 is concentric with the axis of the pivot-pin 3 and itwill thus be seen that the feed-dogs will always be projected substantially simultaneously above the surface of the throat-plate. re-

gardless of the'position of adjustment the fulcrum-screw 33.

WVhen the feed-dogs are at the point of beginning an effective feeding stroke, having moved forward slightly from the position shown in Fig. at. they will assume different elevated positions above the throatplate, as shown in Fig. 5. The risingpin 30 carried by the main feed-bar 10 will have rocked the secondary lever 28' and lifted the feed-dog26 above the level of the primary feed-dog 23. This differential lifting action occurs because the distance betweenthe pin 30 and the fulcrum-screw 33 is less than the distance between the pin 30 and the fulcrum-pin 7.

In moving from the position shown in Fig. 5 to that shown in Fig. 6, wherein the secondary feed-dog is shown disappearing below the level of the throat-plate. thefeedrocker will have moved about three-quarters of the distance to the rearward extremity of its throw indicated by the dotted cir- It will thus be seen that the feed dog 26 becomes ineffective while the pri mary feed-dog 23 still occupies a position above the throat-plate intermediate the extremes .of its effective feeding stroke. The

of the feed-bar 10 and partly by the feedadvaucing movement of the feed-bar 10 which will impart a corresponding lengthwise movement to the feed-bar 28. This movement will rock the anchor-link or differentiator 34: toward a vertical position indicated by the line If and consequently raisethe fulcrum-screw to a higher position, thus lowering the feed-dog26. Y

It is to be understood that the usual foot 38 pressed downwardly by a spring (not shown) cooperates with the forward feed- -dog 2st to advance the work, while a secondary presser-foot 39, mounted on the foot 38 for yielding movements relative thereto, is provided to cooperate with the feed-dog 26.. The secondary presser-foot 39 is mounted directly in rear of the needle n and has a cylindrical shank 40 which slides in an apertured bearing boss 41 formed on the shank of the main foot 38. A collar 42 limits the downward movement of the foot 39 under the influence of the coiled spring 43; the limit of upward movementof the foot 39, relative to the foot 38, being determined by the lower end of the bearing boss 41. The spring 43 surrounds a guide-pin H fixed to the shank of the main foot 3S and the lower end of said spring' is received within a recess in the upper surface of the foot 39.

It will be seen that the present embodi ment of the invention utilizes, in addition to the well known four-motion feed, but two essential parts, i. e., a secondaryfeeds member and an anchor-link, or differentiator, to secure a differential feedingaction. The construction is thereby rendered extremely simple and compact.

. Having thus set forth the nature of the invention, what I claim herein is 1. Differentialfeeding mechanism for sewing machines comprising, in combination, a sup-porting frame, a primary feedbar carrying a feed-dog, a secondary feedbar carrying a feed-dog and pivoted to said primary bar for differential rising and fall-v ing movements relative thereto, said secondary feed-bar having a slot, and adjustable connections between said slot and frame for -varying the said differential movements.

2. Differential feeding mechanism for sewing machines, comprising, in combinatlon, a frame, primary and secondary feeddogs, carriers therefor, one of said carriersbeing supported by the other for differential rising-and-falling moven'ients and substantially equal feed and return movements, means for actuating one of said carriers, and a link directly connecting the other of said carriers with the frame.

3. Differential feeding machanism for sewing machines comprising, in combination, a frame, pivot-ally connected primary and secondary feed-bars arrying feed dogs, means for actuating one of said bars and a single pivoted link bar directly connecting 4 tion, a frame, primary and secondary feeddogs, primary and secondary levers carrying said feed-dogs and pivotally connected together for differential rising-and-falling movements relative to one another, actuating mechanism for imparting operative movements to said primary lever, and a .single upright anchoring link pivotally connected at its upper end to said secondary lever and at its lower end to the frame.

5. Feeding mechanism for sewing machines comprising, in combination, a supporting frame, primary and secondary feedbars pivotally connected for differential rising and falling movements, means for imparting four-motion movements to said primary feedbar, a link connected at one end directly to the frame and at its opposite end directly to said secondary feed-bar, and means whereby connection between said secondary feed-bar and said link from the pivotal connection of said feed-bars may be varied.

6. Differential feeding mechanism for sewing machines, comprising, a frame, primary and secondary feed-levers extending substantially in the same direction throughout their length and pivotally connected together between their ends, a feeddog carried at the forward end of each of said levers, a feed-rocker pivoted to the frame and supporting the rear end of said primary lever, means for raising and lowering said primary lever and a link directly connecting said secondary lever with the pivotal connection between the feed-rocker and the frame.

7. Differential feeding mechanism for sewin machines comprising, primary and secondary feed-dogs, means for imparting the distance of the point of equal feed-and-return and differential rising-and-falling movements to said feeddogs, the parts being so constructed and arranged that the operative surfaces of the feed-dogs are projected substantially simultaneously above the throat-plate, and means whereby said differential movements may be adjusted without varying the relative timing of the projection of said feed-dogs above the throat-plate.

'8. Differential feeding mechanism for sewing machines, comprising, a frame, a primary lever carrying a feeddog, means for imparting four motions thereto, a :slotted secondary lever carryingla feed-dog, connections between said levers, whereby operative movements imparted to said primary lever are transmitted to said secondary lever, a link connected at one end to a fixed point on the frame, a pin carried by said link and adjustably secured within the slot in said secondary lever, said slot being substantially concentric with said fixed point when the active surfaces of the feed-dogs are substantially coincident with the upper surface of the throat-plate,

9. Feeding mechanism for sewing machines comprising, in combination, a frame, a feed-bar, two feed-dogs carried by said feed-bar for differential times of contact with the work and a single positioning link between one of said feed-dogs :and the frame.

10. In a sewing machine, in combination, a frame, a reciprocating fulling-feed, a stitch-spacing feed, carried by said fallingfeed. said feeds having substantially equal feed and return movements, and a single positioning link between said stitch-spacing feed and the frame of the machine for differentiating the times of work engaging 85 contact of said feeding members.

In testimony whereof, I have signed my name to this specification.

ALBERT H. DE VOE. 

